1. Field of the Invention
The present invention relates to a front end assembly for an automobile vehicle.
2. Background Art
Conventional front end assemblies are often made by stamping and welding together several individual frame components. One of the major challenges for manufacturing is to maintain rigidity because these assemblies are often a combination of a number of various frame parts. As each of the frame parts are attached to form subassemblies and then are attached to the body portion of the vehicle, it becomes more difficult to achieve the necessary or desired stiffness in the front end. This problem is sometimes referred to as “matchboxing.” Matchboxing is a phenomenon that occurs when the sheet metal portion of the vehicle is attached to the frame and tends to sway on a hinge point and move from a desired perfect square orientation to a parallelogram orientation. Distorting the sheet metal in this manner may result in poor natural frequency characteristics of the front end structure.
Hydro-formed tubular elements are increasingly being used in the construction of vehicle body structures. Hydro-forming is a metal forming process that uses high-pressure fluids to outwardly expand tubular blanks to conform with the surfaces of a die cavity of a die assembly to form a contoured hydro-formed part.
Vehicle front end assembly processes have yet to take full advantage of the capabilities of tubular hydro-formed parts. A number of prior patents have described the use of tubular members in hybrid front end assemblies, but fail to address the matchboxing issue. For example, Gerricke et al., U.S. Pat. No. 6,416,119 B1, describes a vehicle front end constructed through the use of hydro-formed tubes. In Gerricke, a first body structure formed from a plurality of tube members and a second body structure formed from sheet metal are welded to each other in a sandwiching relationship. However, this method is still subject to matchboxing because the sheet metal structure can be distorted as it is secured to the tube members.
There is a need for a front end construction that may incorporate the use of hydro-formed tubes that provides superior stiffness and rigidity when compared to conventional vehicle front end assembly designs. There is a further need for a front end assembly process that minimizes any tendency of the assembly to distort or matchbox. There is also a need to eliminate structural reinforcements, reduce part counts, and improve the durability of the vehicle body.
The above problems and needs are addressed by Applicants' invention as summarized below.